Variables constant pressure pump control called constant variable pump, which controls shown in Figure 1. Variable pump repair phone, where 1 is the control slide valve, pressure regulator spring 2, 3 is a control cylinder, 1 and 2 collectively for constant pressure valve. When the system pressure is low, there is no right to control cylinder pressure oil control cylinders run right under the action of the spring of the variable displacement pump, pushing the variable mechanism of the pump, the pump in the maximum displacement state. When the system pressure increases to the set pressure of constant pressure valves, hydraulic pressure control spool ends more than a spring force of the pressure regulator valve to the right, the right pressure oil into the control cylinder, push the control cylinder run to the left, then push the variable mechanism of the pump, the pump is reduced variable displacement pump refinement, thus reducing the output flow, pump working pressure with constant pressure variable flow pump 123 control principle reduce the control variable pump control principle, where a for the control slide valve, 2 is a pressure spring, is a control cylinders 3, 4 for the throttle (usually proportional valve), 1 and 2 collectively known constant flow valve, the spring constant differential pressure valve is generally adjusted in advance, does not change. Pressure oil pump action all the way on the left side of the pump variable valve constant maintenance, the other way through the right side of the throttle valve and X port role in constant valve. Because after the throttle valve, the control oil pressure constant flow valve there are left and right ends of the pressure differential. When the load pressure increases, the right end of the control oil pressure constant flow valve plus differential pressure of the spring is greater than the set pressure of the left end of the pilot oil pressure, constant flow valve is switched to the right end position, the control piston back pressure relief chamber, the front chamber pressure oil push control cylinders right line, increasing displacement hydraulic pump, hydraulic pump discharge pressure increases, constant pressure to increase oil control valve left, constant valve is switched to the left position, the control of oil pushing control cylinder hydraulic pump discharge reduce the amount to the position before the change. Variable pump maintenance, | variable pump | Hydraulic from Jinan Jing Jing Chong Chong Hydraulic Machinery Limited. Jinan Jing Chong Hydraulic Machinery Co., Ltd. (www.jnjcyy.com) (www.jnjcyy.com) strong, credible, in Jinan, Shandong mining machinery industry has accumulated a large number of loyal customers. The company better work attitude and continuous improvement to create innovative ideas will lead crystal hydraulic and you hand into the brilliant, for a better future!